I don’t think everyone in the group is crushing on Haruhi. Kyoya, Hunny, and Mori have literally showed 0% interest in her (romantically). At the very least, there has been no indication they have feelings for her.
However, Kaoru showing interest kind of surprised me. I do agree that this manga should be considered a love triangle (square? Lol). It just seems a bit thrown out of nowhere that Kaoru suddenly had feelings for Haruhi even though it seemed like he only cared for her as a friend, especially when Hikaru was the one to develop feelings first. Not sure what direction this is gonna go but still it’s a bit odd lol